One piece sofa



FIG. 1 is a perspective view of a one piece sofa showing my new design;

FIG. 2 is a front view of a one piece sofa showing my new design;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof; and,

FIG. 6 is an end view thereof. 

The ornamental design for a one piece sofa, as shown and described. 